Chlamydia pneumoniae (CP) causes frequently nosocomial pneumonia and other inflammations of the upper and lower airways. Initially reports on the association between infection with CP and ischaemic heart disease (IHD)were published in 1988 by Saikku et al. who found a higher antibody titre against CP in acute myocardial infarction and sudden cardiac death as compared with a control group. The mechanism of this phenomenon is explained by the action of Chlamydi- ae on LDL-cholesterol, cytokines, the tumour necrotizing factor with a subsequent effect on the vascular wall. The authors assessed IgG and IgM antibodies in 39 elderly men using the immunofluorescent method. In addition they assessed the total cholesterol, LDL-cholesterol, triacylglycerol and fibri- nogen. They divided the group into a sub-group with manifest IHD (n=22) and a control group without detectable IHD (n=17). In patients with IHD they found an insignificantly higher preva- lence of Ig antibodies against CP as compared with the control group (31.8% and 29.4% resp.).IgM antibodes were found more frequently in the control group as compared with patients with IHD.Total cholesterol and triacylglycerol were insignificantly higher, HDL cholesterol was lower in patients with IHD as compared with controls. Fibrinogen was paradoxically insignificantly higher in controls as compared with patients with IHD. The authors explain these findings by the fact that the group was formed by elderly men (mean age 73 and 68 years resp.) who had an equal chance of CP infection.At this age arteriosclerosis is already developed and the differences are only in severity and site of the process. In the conclusiuon the authors state that the role of CP, as well as of other microorganisms in the pathogenesis of atherosclerosis is probable, although their investigation did not confirm it unequ- ivocally. It is important to consider also possible interactions of many known and newly detected risk factors.

        Key words: Chlamydia pneumoniae - Atherosclerosis - Ischaemic heart disease.